Stretchable textile article and method



Aug. 1, 1967 w. M. HARRIS 3,333,314

STRETCHABLE TEXTILE ARTICLE AND METHOD Filed Feb. 28, 1966 5 Sheets-Sheet 1 INVENTOR. W1 LLARI) M. HAERLS BYM 166%, @111! 4 ATTORNEYS Aug. 1, 1967 w. M. HARRIS STRETCHABLE TEXTILE ARTICLE AND METHOD 3 Sheets-Sheet 2 Filed Feb. 28, 1966 F H I INVENTOR WILLARD M. H

ARES.

ATTORNEYS 1967 w. M. HARRIS 3,333,314

STRETCHABLE TEXTILE ARTICLE AND METHOD Filed Feb. 28, 196 6 5 Sheets-Sheet 3 INVENTOR WI LLARD M. HAREEa 21 9 -10 BYM55ZZJ%,L%M

ATTORNEYS United States Patent AND This invention relates generally to a new stretchable textile article that is knitted or woven with a crimpable synthetic yarn, and to a novel method and means for providing a high degree of stretchability in the textile article. The present invention is patricularly adapted for providing marked stretchability in ladies stockings knitted of self-crimping yarn, known as Cantrece" yarn.

The manufacturer of this self-crimping yarn, i.e., E. I. du Pont de Nemours & Co., Inc., describes in a publication entitled, Producing Ladies Full Length Seamless Hosiery of Du Pont Cantrece Nylon Hosiery Yarn, Bulletin No. 58, Dec. 10, 1965, two methods of developing the crimp or curl by the use of steam and the recommended knitting procedure to be followed. In one recommended method, the stockings are laid out in substantially straight condition on trays and in piles with a very few stockings in each pile so as to provide a minimum of fabric restriction while the crimp is being developed. The trays of stockings are then placed in a steam conditioner that reaches a maximum temperature of 210- 212 F. for thirty minutes. In the other method described in said Du Pont publication, the stockings are loosely placed in dye bags and these dye bags placed in a fifty-pound rotatin-gdye machine. The dye tub is rotated to tumble the bags of stockings and steam is applied for a thirty-minute cycle.

When the stockings of Cantrece yarn are knit in the recommended manner and finished in either of the abovedescribed methods, they have very little stretch and must be manufactured in about eight different sizes in order to fit all the size ranges.

As indicated above, the use of the self-crimping Cantrece yarn to date has been limited to conventional length and foot size stockings in which the Cantrece yarn provides a slightly textured appearance and soft feel that is not obtainable with the regular denier monofilament nylon yarn in conventional stockings, and the Cantrece yarn per so cannot be used to obtain the so-called stretch stocking which is stretchable when worn to fit a number of leg and foot sizes.

In accordance with the present invention, I have discovered a method and means for knitting and then treating or processing stockings, or other articles knitted or woven with the Cantrece yarn, which causes a more complete development of the crimp or curl in the yarn to impart to the stockings or other articles a decided stretch property such that these products can be stretched to accommodate a number of foot and leg sizes in the stockings and similarly a number of sizes in other garments which are knitted or WOVGl'lWilll the Cantrece yarn and which are subjected to our special treatment. This treatment is based on my discovery that the Cantrece yarn stocking or other article, which does not have stretch properties, can be given these properties by rapidly vibrating the product in the presence of heat, preferably steam under pressure. This totally unexpected stretch property is not obtainable from either of the procedures described in the Du Pont publication, supra, including the one in which the stockings are simultaneously heated and rotated in a dye machine. In other words, agitation of the product by rotating, tumbling or the like will not produce the stretch property and the latter is obtained only in accordance with my discovery, by subject- 3,333,3 l4 Patented Aug. 1, 1967 stockings, causes the yarn to develop a crimp character- 7 istic which it does not have at the time of knitting of the stocking and which is developed only to a mild or definitely limited extent in the normal processing of the stockings in the usual manner or in accordance with either of the procedures recommended by the manufacturer of the yarn.

As an aid in the development of the crimp in the yarn and to compensate for the shrinkage of the stocking during development of the crimp, I have found that the stitch loops should be initially knit longer or larger than that recommended by the manufacturer of the yarn. The longer or larger stitch loops provide a greater length of the yarn in the fabric so that the crimp may be more fully developed and the stocking will have a much greater degree of stretchability. Thus, the knitting of larger than normal stitch loops and the substantial rapid vibration treatment which characterizes my invention produces for the first time a truly stretch stocking, or other product made from the Cantrece yarn and treated in this manner and which result is not obtainable from the same yarn by conventional procedures.

Thus, the method of my invention has made it possible for the first time to obtain on a satisfactory commercial basis a truly stretch stocking employing Cantrece yarn with its desirable characteristics. Also, this avoids the necessity of throwing or twisting the yarn as is normally done with conventional 15 denier monofilament nylon yarn to produce a stretch stocking therefrom.

The method of my invention also has made it possible for the first time to produce a support stocking employing Cantrece yarn. A support stocking can be produced by knitting multiple ends of monofilament Cantrece yarn and forming larger than normal stitch loops in each course, and then rapidly vibrating the stocking in accordance with my invention.

While particular reference is made herein to stretch and support stockings, it is to be understood that I contemplate the employment of the method and means of my invention for processing of other articles or fabric, either knitted or woven, from which different types of products may be made and in which stretch properties are desired. a

For illustrative, but non-limiting purposes, the method and means of my invention are described hereinafter as applied to ladies stockings knitted from Cantrece yarn and the stockings treated in accordance with my invention for producing stockings that have sufficient stretch to accommodate various foot and leg sizes.

Details of the invention will appearas the description proceeds, when taken in connection with the accompanying drawings in which- FIGURE 1 is a side elevation of a greige stocking, illustrating the appearance after knitting and with the toe opening closed;

FIGURE 2 is a side elevation of the stocking shown in FIGURE 1 and illustrating the manner in which the stocking is reduced in size after it is subjected to rapid vibrations in the presenceof steam;

FIGURE 3 is a side elevation of the stretch stocking of the present invention after it is finished and boarded to shape;

FIGURE 4 is a greatly enlarged View of the fabric in the leg portion of the stocking shown in FIGURE 3, being taken in the area of the dotted circle 4 therein, and being partial-1y stretched to more clearly illustrate the manner in which the stitch loops are deformed by the crimping of the monofilarnent yarn;

FIGURE 5 is an isometric view of the apparatus for steaming and vibrating the stretch type stockings;

FIGURE 6 is a longitudinal vertical sectional view through the steam cabinet and illustrating the tray of stretch stockings therein;

FIGURE 7 is an enlarged fragmentary vertical sectional view taken substantially along the line 77 in FIG- URE 6;

FIGURE 8 is a side elevation of a support stocking in finished and boarded condition and produced in accordance with the present invention;

FIGURE 9 is a greatly enlarged view of the fabric in the leg of the support stocking of FIGURE 8, being taken in the area enclosed by the dotted circle 9 and being partially stretched to more clearly illustrate the manner in which the stitch loops are distorted when the crimp in the yarn is developed in accordance with the present invention;

FIGURE 10 is a fragmentary isometric view of the upper portion of a vertically disposed steam cabinet and illustrating the manner in which the support stockings are hung therein to impart rapid vibrations thereto during the steaming cycle; and

FIGURE 11 is an enlarged fragmentary isometric view illustrating the manner in which the support stockings are tied together and supported on the vibrating hook devices in the steam cabinet.

While the present invention has made it possible to produce both truly stretch stockings and support type stockings of self-crimping Cantrece yarn, it has been found that the stretch stockings and support stockings should be maintained in different positions while the rapid vibrations are applied thereto, in order to obtain the optimum crimp development in these two different types of stockings.

Generally, the method for developing the crimp of the Cantrece yarn of the stretch stocking includes laying the stockings in a substantially straight horizontal position in a tray, placing the tray in -a steam pressure cabinet, and applying rapid vibrations to the tray and the stockings therein during the steaming cycle. The method for developing the crimp of the Cantrece yarn of the support stocking includes tying the welts of a group of the stockings together, hanging the stockings on a support so that they extend downwardly therefrom in a loose, substantially vertical position in a steam cabinet, and applying rapid vibrations to the support and the stockings hanging therefrom during the steaming cycle.

The stretch stocking of the present invention and the apparatus for fully developing the crimp of the selfcrimping yarn therein are illustrated in FIGURES 1-7. As shown in FIGURE 1, the stretch stocking is in the form of a substantially straight tube after it is knit on a circular knitting machine. The stocking includes a turned welt 20, a shadow welt 21, a leg 22, and a foot including heel and toe pockets 24, 25 and an instep portion 26. The courses of the leg 22 and circular knit portion 26 of the foot are knit of monofilament denier self-crimping Cantrece yarn. During the knitting operation, the number of courses recommended by Du Pont are knit in the leg and foot but the stitch loops are made larger or longer than normal so that the greige stocking is longer than normal. For example, Du Pont recommends that the greige stocking for 9 /240 medium be knit to measure 37 inches on a size 11 sizing form. My stretch stocking is knit with the same number of courses but with longer stitches so that it will measure 39% inches on a size 11 /2 sizing form. These longer stitch loops aid in the more complete development of the crimp in the yarn, in accordance with my invention, compensate for the shrinkage of the stocking and provide a greater length of yarn in which the crimp can be developed.

FIGURES 5, 6 and 7 illustrate the means particularly adapted for developing the crimp or curl in the selforirnping yarn to thereby provide substantial stretchabihty to the stretch stocking. As the crimp is developed in the greige stocking, the yarn has a strong tendency to curl or coil, thereby causing the stocking to contract both coursewise and walewise, substantially as shown in FIGURE 2.

The elongate horizontal steam cabinet 30 (FIGURE 5) is provided with a closure door 31 at one end and trackways 32 extending longitudinally along the lower floor portion thereof. Similar tracks 33 are disposed outside of the entrance end of the steam cabinet 34? and support the roller wheels of a cart 34. A support frame 35 is connected at one end to one end of the cart 34 and has an upper U-shaped support frame which is supported in spaced relationship above the cart 34.

A stocking receiving tray 40 is resiliently supported at each corner on the frame 35, as by springs 41 which surround guide pins 42. The upper ends of the guide pins 42 are supported in the frame 35 and the medial portions thereof penetrate support angle clips 43 that are secured adjacent each corner of the tray 40'. Springs 44 are connected at one end to one end of the tray 46 and at their other end to the vertical legs of the frame 35 to prevent excessive endwise movement of the tray 40.

A cam shaft 45 is supported for rotation adjacent opposite ends in the side walls of the steam cabinet 3t) and has a cam member 46 fixed on the medial portion thereof. One end of the cam shaft 45 extends outwardly beyond the steam cabinet 36) and is drivingly connected to a variable speed electric motor 50. The tray 40 is preferably provided with perforations to permit the escape of any condensation from the tray and a liner 51 of Dacron material is provided on the inside of the tray 40 to prevent direct contact of the stockings with the metal tray 40 during the steaming operation.

The steam cabinet 39 is provided with the usual means for supplying steam under pressure at a predetermined temperature for a predetermined length of time or cycle. Details of the steam supplying means of the steam cabinet 30 are shown and described in US. Patent No. 2,351,063, issued Iune 13, 1944, and to which further reference may be made for the details disclosed therein.

In developing the crimp of the stretch stocking, three dozens of the greige stockings, as shown in FIGURE 1, are laid out in the tray 41} with one dozen in each of three loose piles (FIGURE 7). The cart 34 is moved into the steam cabinet 30, as shown in FIGURE 6, so that the lower surface of the medial portion of the tray 40 is resiliently supported on the cam 46. The motor 50 is started to impart rotation to the cam shaft 45 and the cam 46 so that approximately 450 vibrations per minute are imparted to the tray 40 and the stockings therein. Steam is then fed into the steam cabinet 30 to build up the pressure to about 20 to 30 pounds and to raise the temperature therein to 240 F. This vibration and steaming is continued for a one-minute cycle.

Upon completion of the steaming cycle, the cart 34 is moved back out on to the rails 33 and the stockings in the tray 40 are then removed, having been shrunk or contracted to substantially the condition shown in FIGURE 2 and with the crimp or curl in the yarn having been developed to a substantially high degree.

The stockings are then finished by dyeing and boarding to set the finished shape therein, as shown in FIGURE 3. The stitch loops of the finished stocking and the monofilament yarn Y in each course of the stocking (FIGURE 4) has the crimp developed to such an extent that the stitch loops are distorted as the yarn has a strong tendency to crimp and curl upon itself, thereby imparting a high degree of stretchabihty to the stocking. The fabric shown in FIGURE 4 is in a partially stretched condition to more clearly illustrate the manner in which the yarn tends to distort to thereby distort the stitch loops. When the fabric is relaxed, the yarn and stitch loops distort to a greater degree to raw t e fabric up in all directions.

The present stretch stocking of self-crimping yarn, as shown in FIGURE 3, is preferably knit in three sizes which have sufficient stretchability to fit the complete range of foot and leg sizes, heretofore requiring the production of eight or more different sizes.

The finished support stocking of the present invention, broadly indicated at H in FIGURE 8, is initially knit with three ends of monofilament denier self-crimping yarn in plated relationship in each course, as shown at Y-l, Y-Z and Y-3 in FIGURE 9. During the knitting of the support stocking, the stitch loops are again formed larger or longer than normal.

After knitting, the upper welt portions of a dozen greige stockings are rolled together and secured together by tying a knit looper clip 55 therearound, as shown in FIGURE 11. Three bundles of these support stockings are then hung on hooks 56 (FIGURE 10), which are preferably covered with a nylon fabric. The hooks 56 are fixed on a vibration imparting shaft 60 that is supported for oscillation in opposite side walls of a vertical steam cabinet 61. The steam cabinet is provided with the usual means for maintaining steam under pressure at the desired temperature for the desired steaming cycle. The steam supply means is fully disclosed and described in U.S. Patent No. 2,321,453, issued June 8, 1943, which may be referred to for further details there-of.

After the door 62 is closed and locked in position, with the bundles of stockings supported on the books 56, rapid vibration is imparted to the hooks S6 and then steam under pressure enters the cabinet 61 to maintain the temperature at 260 F. for a one-minute cycle.

The rapid vibrations are imparted to the shaft 60, the hooks 56, and the support stockings H hanging therefrom by means of a lever '70, the lower end of which is suitably connected to one end of the shaft 60 (FIGURE 10). The upper end of the lever 70 is connected in offset relation to a circular plate '72 by means of a connecting link '73. The plate 72 is secured to the output shaft of an electric motor 74 which is supported on the upper wall of the steam cabinet 61. During the steam-setting cycle, the motor '74 is rotated at 1140 r.p.m. to thereby impart rapid vibration to the hooks 56 and the support stockings H hanging therefrom as indicated in dotted lines in FIG- URE 11.

This rapid vibration of the support stockings H during the steaming cycle causes the crimp or curl to be deve1- oped to a high degree in the self-crimping yarns Y-1, Y-Z and Y-3 in each course of the fabric. This crimp development causes a substantial contraction of the support stockings and imparts substantial stretchability to the fabric. The support stockings are then dyed and boarded in the usual manner.

The distortion of the yarns and stitch loops is shown in the partially stretched fabric of FIGURE 9. Each crimped yarn straightens somewhat when the support stocking is stretched and they each have a strong tendency to return to the distorted and crimped condition. Since each crimped yarn has a strong tendency to return to the distorted condition it was in when heat-set in relaxed condition, the three yarns combine to provide substantial compressive force on the leg of the wearer. While the support stocking is described as being knit of three monofilament yarn ends, it is to be understood that the stocking may be knit of two or more ends, if desired.

The stockings of the present invention have been described as being knit with plain stitches throughout. However, it is to be understood that various patterns may be formed by knitting a combination of plain stitches with other types of stitches, such as tucks and/or floats in the desired pattern.

The vibrating means disclosed in the present application may be useful in developing crimp or otherwise processing articles of clothing, other than stockings. For

xample, the vibrating means could be used to process sportswear, sweaters, bathing suits, and the like. Further, the vibrating means is not limited to use with textile articles but may be used for shaking and vibrating (as in the mining industry), for cleaning, smoothing and polishing small parts (as in the metal working industry), for filling voids in the materials placed in molds, or for aiding in the flow of granular materials being conveyed from one place to another.

The present invention has been described in detail above for purposes of illustration only, and is not intended to be limited by this description or otherwise, except as defined in the appended claims.

I claim:

1. In a process for markedly increasing the stretchability of a textile fabric formed of continuous filament synthetic yarn which has the ability to crimp and curl to a limited extent in response to being heated, the improvement comprising the step of applying moist heat under superatmospheric pressure and while applying rapid mechanical vibrations below the ultrasonic range to the heated fabric to impart the enhanced crimp and curl to the yarn and substantially increase the stretchability of the fabric.

2. A process as defined in claim 1 and in which the fabric is heated by moist heat to a temperature between approximately 240 F.-260 F.

3. A process as defined in claim 1 and in which the fabric is heated by subjecting it to steam under pressure.

4-. A process as defined in claim *1 in which the textile fabric is a knitted ladies stretch stocking.

5. A process according to claim 1 including the step of knitting at least the leg and foot of larger than normal stitch loops.

References Cited UNITED STATES PATENTS 2,439,815 4/1948 Sisson. 2,699,592 1/1955 Newnam 26-18.5 2,730,786 l/1956 Kindstrand et a1. 2618.5 X 2,742,773 4/1956 Chambers et a1. 26-18.5 X 2,907,094 10/1959 Murray 61; a1. 2,919,534 1/1960 Bolinger et al. 3,017,685 1/1962 Heberlein. 3,021,588 2/1962 Bolinger. 3,038,235 6/ 1962 Zimmerman. 3,084,020 4/1963 Loosi 2876 3,090,666 5/1963 Jones 26-18.5 X 3,125,848 3/1964 Baebler. 3,181,224 5/1965 Tanner 2872 3,197,978 8/ 1965 Sheeler. 3,271,837 9/1966 Au et al. 2876 X FOREIGN PATENTS 606,221 10/1960 Canada. 1,342,601 9/1963 France.

950,429 2/1964 Great Britain.

MERVIN STEIN, Primary Examiner. R. FELDBAUM, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,333 ,314 August 1 1967 Willard M. Harris pears in the above numbered pat- It is hereby certified that error ap tent should read as ent requiring correction and that the said Letters Pa corrected below.

Column 6, line 38, for the claim reference numeral "1" read 4 Signed and sealed this 27th day of August 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. IN A PROCESS FOR MARKEDLY INCREASING THE STRETCHABILITY OF A TEXTILE FABRIC FORMED OF CONTINUOUS FILAMENT SYNTHETIC YARN WHICH HAS THE ABILITY TOCRIMP AND CURL TO A LIMITED EXTENT IN RESPONSE TO BEING HEATED, THE IMPROVEMENT COMPRISING THE STEP OF APPLYING MOIST HEAT UNDER SUPERATMOSPHERIC PRESSURE AND WHILE APPLYING RAPID MECHANICAL VIBRATIONS BELOW THE ULTRASONIC RANGE TO THE HEATED FABRIC TO IMPART THE ENHANCED CRIMP AND CURL TO THE YARN AND SUBSTANTIALLY INCREASE THE STRETCHABILITY OF THE FABRIC. 